There are three forms of muscle contractions, concentric, eccentric and isometric. Pilates works all of them, let's see how using an easy example, the frog on the reformer.
Concentric contraction involves shortening a muscle as it performs work. Think of a biceps curl. In the frog exercise, concentric contraction occurs in the second part of movement, when you bend your knees toward your chest while still resisting the spring so the reformer machine doesn't take over. Your hamstring muscles shorten as they perform the work of bending your leg but keeping them sliding back at a 45 degrees angle.
Eccentric contraction requires a muscle to lengthen as it manages a load. This happens in the first movement of the frog exercise, when your legs extend forward to their full length. In this movement, your quadriceps muscles use eccentric contraction to extend away from the body while managing the weight of your leg and the resistance of the springs.
Isometric contraction entails the static hold of a workload, instead of a movement. This can be used as an add-on towards the end of the frog exercise. When your legs are extended just add a 10-second hold resisting against the spring. Your abdominal muscles will work in isometric contraction here to manage holding the weight of your legs. Isometric holds are likely to fatigue your muscles and are usually better used at the end of an exercise so they don't deteriorate the quality of movement during the eccentric and concentric phases of your exercises.
What are the benefits of eccentric control?
The eccentric work is where Pilates gets its reputation for being a great way to both lengthen and strengthen muscles in fitness and in rehabilitation.
Studies show that eccentric exercise results in less oxygen consumption, greater force production, and less energy expenditure than concentric exercise. Consequently it is a great way to strengthen weaker or injured muscles and building up their endurance. It has also been proven to be a great method of strengthening for older adults.
When you resist the springs on Pilates apparatus, use the magic circle or exercise band, the lengthening contraction often happens during what you might think of as the return portion of the exercise. So whether you go for a mat class or use the equipment, you are guaranteed to exercise your muscles eccentrically in every session and build some strength in length.
Want to work your muscles in every way? Check out our great classes at BPS Tensegrity studios Alexandria, Ashbury or Caringbah.